A continuing demand for additional digital communication services has prompted services providers to investigate additional ways to further optimize the bandwidth and signal transfer capabilities of existing communications systems. In many cases, the existing communication systems include telephone networks using metallic twisted pairs that were configured to communicate a single channel of analog voice signals having a relatively low frequency range (e.g., predominantly below about 10 kHz).
Increasingly, telephone networks are used to carry transmissions other than analog voice signals. For example, a variety of digital services, such as Integrated Services Digital Network (ISDN), Digital Subscriber Line (DSL), Asymmetric Digital Subscriber Line (ASDL), High Bit-Rate Digital Subscriber Line (HDSL) and Very High Bit-Rate Digital Subscriber Line (VDSL) are communicated using communications links in telephone networks.
Existing telephone networks generally include various signal discontinuities. For example, terminated and non-terminated bridged taps may exist along communications links that introduce the signal discontinuities. At the relatively low frequencies used in analog voice communications, the presence of such discontinuities did not significantly affect signal transmission along a communications link in the telephone network However, since the foregoing digital services generally operate at much higher frequencies than analog voice transmissions, the presence of the various signal discontinuities can create problems with their transmission.